Harris went from being a first-round pick as an offensive tackle in 2003 to becoming the main target of fan criticism as he struggled with penalties and pass protection. He was eventually relegated to playing as a backup and on special teams last season with the 49ers.

"Last year was rather difficult. Anybody who has gone through a year like last year would find it rather challenging," Harris said. "So, from that point of view, yeah, you have to take a step back and reassess yourself, see where you are, and kind of just look yourself in the mirror."

Harris did just that and set out for a fresh start to revive his career. Harris didn't venture very far, signing a three-year, $16 million deal with the Oakland Raiders this offseason.

The deal was a low-risk one for the Raiders who guaranteed Harris only $3 million, essentially giving him a one-year audition to once again be a starting tackle in the NFL.

Harris had an ally in Oakland in offensive coordinator Greg Knapp, who had the same job in San Francisco when Harris was drafted out of Stanford with the No. 26 pick.

"I really liked what I saw in his athletic ability, his smarts, and power," Knapp said. "He's a very good run blocker. He just unfortunately went through what's very tough in this business - three coaches in four years. And so he has unfortunately not had a very strong foundation for him to build from."

The constant changing of coaches made it difficult for Harris to adjust to the NFL. In Oakland, he's had the opportunity to work with assistant Tom Cable, who helped another former first-round pick revive his career in his first year with the Raiders.

Robert Gallery, the No. 2 pick in 2004, struggled with different coaches and schemes in his first three years in the NFL before showing signs of success as a left guard in Cable's zone-blocking scheme last season. The Raiders believe they could have similar success with Harris.

But it took some convincing for Harris to believe it. He said he questioned the Raiders as much as they questioned him when he negotiated his contract to determine if this system which relies more on athleticism and speed than brute power would truly suit his skills.

Coach Lane Kiffin said they have pretty much treated Harris like a rookie, teaching him an entirely new way of playing from scratch and building his confidence back slowly. Harris has quickly become a convert to zone blocking and Cable's teachings.

"I love the system, I love this running system. I think it's a really good fit for me," Harris said. "At first I have to say I was a little bit hesitant coming from the Niners. I was in that system for five years. That's all I did and that's all I knew. But coming here and kind of listening to them talk about it, and then being able to get a chance to play in it, I'm like, 'OK, I see what they're saying.' So I mean, I'm really excited about the system."

The Raiders have been pleased so far in what they've seen from Harris. He played well in the first half last week against Tennessee, not needing much help in pass blocking.

He will have even more responsibility this week when the starting offense is expected to play into the second half in Saturday night's exhibition game against Arizona.

"We weren't conservative as far as him not having to be in certain situations," Kiffin said. "So he did well. There's times at practice guys get into him, get after him. But this will be a really good test for him as far as how long we're going to play. This'll be the most plays he's played, and see how far he can take it."

But the real test will come once the regular season begins, when he will be going up against top pass rushers each week and dealing with crowd noise that contributed to the false starts that marred his tenure in San Francisco.

The pressure on Harris to succeed is high. Having moved from right tackle in San Francisco to the left side in Oakland, he is tasked with the all-important job of protecting franchise quarterback JaMarcus Russell's blind side.

"It is implicit just in that position in that as the left tackle you go up against the premiere defensive lineman and you are the marquee lineman in the sense that you are protecting the quarterback's blind side," Harris said. "All those things go through your mind."